Spacer for carrying optical fibers

Abstract

In an optical fiber carrying spacer which has helical grooves for carrying optical fibers with each groove changing the direction of its helix for each turn about the spacer, each helical groove includes extra-length portions and compensating portions both formed at a smaller angle to a longitudinal axis of the spacer than main groove portions. The extra-length portions are each provided at a position where the direction of the helix changes. The compensating portions are each provided between adjacent extra-length portions at an angular distance ranging from 1/4 to 3/4 of the circumference of the spacer. The spacer effectively prevents stresses from being applied to the optical fibers along the longitudinal direction when the spacer is bent or curved.

We claim: 
     
       1. An optical fiber carrying spacer having helical grooves for receiving optical fibers, each groove changing the direction of its helix for each turn about the spacer, wherein each helical groove includes extra-length portions and compensating portions both formed at a smaller angle to a longitudinal axis of the spacer than main groove portions, each of the extra-length portions being provided at a position where the direction of helix changes, and each of the compensating portions being provided between adjacent extra-length portions at an angular distance ranging from 1/4 to 3/4 of the circumference of the spacer from the direction changing position. 
     
     
       2. An optical fiber carrying spacer as claimed in claim 1, wherein the compensating portions are each provided at an angular distance of about 1/2 of the circumference of the spacer from the direction changing position. 
     
     
       3. An optical fiber carrying spacer as claimed in claim 2, wherein the extra-length portions and the compensating portions have equal length in one turn of the helical groove about the spacer.